Soil, relic ice, permafrost, Hart Ash and granite samples from the Lower Victoria Valley, Beacon Valley, near the Meserve Glacier in Wright Valley, and Kennar Valley to determine the deposition of this ice

Entry ID:
K047_2004_2006_NZ_1

Summary

Abstract:
Ancient glacial ice that has stagnated and lies buried underneath rock debris has been found in the Beacon Valley and more recently in several other valleys. This ice poses the possibility of obtaining a much older climate data than can be obtained from Antarctic ice sheet cores. Soil pits were dug above massive relic ice in the Lower Victoria Valley, Beacon Valley, near the Meserve Glacier in ... Wright Valley, and Kennar Valley and the ice was sampled and a core was sampled to a depth of about 1m. The core was dated using atmospheric 10Be on the >62 micron fraction of sediment from the core. The use of atmospheric 10Be dating to date ice needed its methods developed further and tested against a surface of known age. Samples of Hart Ash between the Meserve and Hart Glaciers in the Wright Valley were collected as they have a known radiometric date of 3.9Ma. Samples of relic ice were taken at 5cm intervals down the ice cores and was analysed for chemical and isotopic analysis. Resistivity soundings (one dimensional, vertical profile) were made in the Lower Victoria Valley and Beacon Valleys at selected locations where relic ice was sampled to help characterize the extent and depth of the relic ice. Samples of granite collected from the Victoria Valley, Wright Valley, Beacon Valley and Kennar Valley, used for fingerprinting were cut and placed in a laser ablated chamber attached to a multi collector mass spectrometer. Lead isotopes 204, 206 and 207 were measured in the feldspar of each sample to show areas of feldspar genesis which are unique to the magma bodies where granitic rocks crystallize. The aim was to establish the setting of these ice bodies and dating the length of time they have been in their present situation.

Quality
During the first season of sampling, all of the frozen samples were lost due to thawing in transit from Antarctica to New Zealand. Samples from the second season of sampling are stored at Victoria University Wellington and available for use.